The present invention relates to measurement instruments and, more particularly, to an instrument that includes a touch screen display to provide flexibility as well as ease of use.
Hand held measurement instruments are growing in popularity because of their small size and increasing functionality. In fact, many such instruments can perform several measurement functions, such as measuring temperature and pressure. These multi-function measurement instruments typically have several generic keys that apply to all measurement functions, such as numeric keys, and several function specific keys that are unique to particular measurement functions, such as a .degree. F./.degree. C. toggle key for the temperature function. However, as the number of measurement functions increases, or as the flexibility of these instruments increases, more and more function specific keys must be added to the instrument. As a result, the instrument becomes very cluttered and confusing, especially in determining which key is used for a particular measurement function.
In an attempt to resolve this confusion and provide an uncluttered, more user-friendly interface, some multi-function measurement instruments include multi-purpose keys that change functions as needed. For example, a row of multi-purpose keys are placed under a liquid crystal device ("LCD") display. The LCD display can provide a label directly above each multi-purpose key to describe the function for that key. These labels, in turn, can be changed as the functionality of the multi-purpose key is changed.
This solution, however, only provides limited help. The main problem is that different measurement functions require different numbers of multi-purpose keys. The measurement instrument must therefore include many different multi-purpose keys, as determined by the measurement function requiring the most such keys. As a result, the instrument once again becomes cluttered with different keys, even for measurement functions that require only a few function specific keys.
Therefore, what is needed is a measurement instrument that supports many different measurement functions but is not cluttered with a vast number of keys. Instead, the number of keys should be limited to that required by a particular measurement function.
Furthermore, what is needed is a measurement instrument that provides a changeable number of keys, such keys being labeled and positioned so that the instrument remains uncluttered and has a user-friendly interface.